1. Field of The Invention
The present invention relates generally to a system for compensating an idle operation and related control method, and more particularly, to a system for achieving a smooth idle operation by compensating for an amount of air supplied to an intake manifold in accordance with changes in electrical loads when peripheral electric device of high loads are activated during the idle operation.
2. Description of Related Art
Generally, a driver starts an automotive vehicle and lets it idle, i.e., a warm-up operation, for a predetermined time, to ensure that the automotive vehicle will run smoothly when the driver accelerates the engine to run the automotive vehicle.
During the idle operation, a control unit senses the operating state of the automotive vehicle or engine using various sensors. The control unit supplies air corresponding to an idle operation state to each cylinder of the engine to achieve an optimal idle operation. As a result, during the idle operation, the engine operates smoothly to improve fuel ratio.
However, when the driver activates electrical devices, such as an air conditioner or head lights, and the engine is not idled-up by pressing on the accelerator pedal, the engine becomes loaded and its rotational frequency (rpm) is sharply reduced.
Conventionally, to compensate for such fluctuation in the rotational frequency and to provide a smooth idle operation, a normally injected fuel amount or spark time is increased or decreased corresponding to an amount of indraft air. Accordingly, the engine may operate normally.
However, when a predetermined, normally injected fuel amount or spark time is compensated and the operation of the engine is changed, as described above, a problem arises in that a rapid compensation is not possible. This is because the amount of air does not change at the same rate or time as the increase in fuel amount.
In addition, fuel is wasted since a large amount of fuel is injected relative to the amount of indraft air at a sudden instant, and at the same time, a large amount of pollutants, due to imperfect combustion, are exhausted.